kc3-lang/gnulib/lib/pipe2.c

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• Hash : ffb0b299
  Author :
  Date : 2010-09-10T11:55:27
  

  fcntl-h: define O_CLOEXEC and O_EXEC if not defined; use new defines
  
  * doc/posix-headers/fcntl.texi (fcntl.h): Document that
  O_CLOEXEC is now defined to 0 if it is not defined, like other flags.
  Also, O_EXEC is now defined to be O_RDONLY if O_EXEC is not defined.
  Similarly for O_SEARCH; this last was already true, but not documented.
  * lib/fcntl.in.h (O_CLOEXEC): Define to 0 if not defined.
  * lib/dup-safer-flag.c (O_CLOEXEC): Remove now-useless #define.
  * lib/dup3.c, lib/pipe2.c, tests/test-dup-safer.c, tests/test-fcntl.c:
  Likewise.
  * lib/popen-safer.c (open_noinherit): Check whether O_CLOEXEC
  is zero, not whether it is defined.
  * tests/test-dup3.c, tests/test-pipe2.c (main): Likewise.
  * lib/progreloc.c (find_executable): Use O_EXEC rather than O_RDONLY.
  * lib/open.c (open): Check for O_SEARCH as well as for O_RDONLY.
  

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• lib/pipe2.c

• /* Create a pipe, with specific opening flags.
     Copyright (C) 2009, 2010 Free Software Foundation, Inc.
  
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2, or (at your option)
     any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License along
     with this program; if not, write to the Free Software Foundation,
     Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include <unistd.h>
  
  #include <errno.h>
  #include <fcntl.h>
  
  #include "binary-io.h"
  
  #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  /* Native Woe32 API.  */
  
  # include <io.h>
  
  #endif
  
  int
  pipe2 (int fd[2], int flags)
  {
  #if HAVE_PIPE2
  # undef pipe2
    /* Try the system call first, if it exists.  (We may be running with a glibc
       that has the function but with an older kernel that lacks it.)  */
    {
      /* Cache the information whether the system call really exists.  */
      static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
      if (have_pipe2_really >= 0)
        {
          int result = pipe2 (fd, flags);
          if (!(result < 0 && errno == ENOSYS))
            {
              have_pipe2_really = 1;
              return result;
            }
          have_pipe2_really = -1;
        }
    }
  #endif
  
  #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  /* Native Woe32 API.  */
  
    /* Check the supported flags.  */
    if ((flags & ~(O_CLOEXEC | O_BINARY | O_TEXT)) != 0)
      {
        errno = EINVAL;
        return -1;
      }
  
    return _pipe (fd, 4096, flags);
  
  #else
  /* Unix API.  */
  
    /* Check the supported flags.  */
    if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_TEXT | O_BINARY)) != 0)
      {
        errno = EINVAL;
        return -1;
      }
  
    if (pipe (fd) < 0)
      return -1;
  
    /* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/pipe.html>
       says that initially, the O_NONBLOCK and FD_CLOEXEC flags are cleared on
       both fd[0] amd fd[1].  */
  
    if (flags & O_NONBLOCK)
      {
        int fcntl_flags;
  
        if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0
            || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
            || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
            || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
          goto fail;
      }
  
    if (flags & O_CLOEXEC)
      {
        int fcntl_flags;
  
        if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0
            || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
            || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
            || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
          goto fail;
      }
  
  # if O_BINARY
    if (flags & O_BINARY)
      {
        setmode (fd[1], O_BINARY);
        setmode (fd[0], O_BINARY);
      }
    else if (flags & O_TEXT)
      {
        setmode (fd[1], O_TEXT);
        setmode (fd[0], O_TEXT);
      }
  # endif
  
    return 0;
  
   fail:
    {
      int saved_errno = errno;
      close (fd[0]);
      close (fd[1]);
      errno = saved_errno;
      return -1;
    }
  
  #endif
  }
  

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